Ill 



det — rigtignok énestaaende Tilfælde, i hvilket jes har 

 paayist en Oxydation af Bundprøven ved dens Henliggen i 

 Luften. En saadan Forandring skulde altsaa foregaa med 

 stur Langsomhed i Havet. 



Jeg vil imidlertid langtfra paastaa, at den OTenstaaende 

 Forklaring er den rigtige : jeg indrømmer, ;tt den staar 

 paa meget svage Kodder, og har derfor blot fremsat den 

 som en Gisning, for at henlede Opmærksomhedén paaSlam- 

 arternes eiendommelige Oxydationsforhold. Talrige andre 

 Omstændigheder maa ogsaa tåges i Betragtning ved Afgjø- 

 relsen af dette Spørgsmaal. Saaledes er det f. Ex. utvivl- 

 sonit. at de i Slammet forekommende Dyr bidrager til dets 

 Oxydation. Især tinder man otte en Udskillelse af rødt 

 Jernoxyd paa de Punkter af Leret, hvor Annelider kar 

 gravet sig Gange. Mange Foraminiferer virker i den samme 

 Retning, idet de danner sig stærkt jernoxydholdige Skaller. 

 Som forud omtalt er Rhabdammina-Leret meget fattigt paa 

 Dyrelevninger. 



En at de Stene. der blev fundne i Østhavet paa Stat. 

 267, har jeg nærmere undersøgt. Det var en tinkornig, 

 blaagraa Sandsten med stærkt kalkholdig! Bindemiddel (Kalk- 

 sandsten). I det saltsure Udtræk af denne Sten — til- 

 beredt paa samme Maade som i Bundprøverne — fandtes: 



1.38 pCt. FeO og 0.59 pCt. Fe 2 3 . 

 Altsaa et lignende Forhold som i Rhabdammina-Leret. 



I Overensstemmelse med hvad der er sagt under Be- 

 skrivelsen af det graa Ler, vil det være indlysende, at vi 

 ikke med Nøiagtighed kan bestemme Rhabdammina-Lerets 

 sydlige og vestlige Gfændser, da vi mangler de nødvendige 

 Observationer fra -denne Del af Havet. Den sidste holland- 

 ske Expedition i 1878 har foretaget endel Dybdemaalinger 

 i Retningen Vardø — Beeren Eiland. men Bundens Beskaf- 

 fenhed er ved denne Anledning ikke blevet nærmere andersøgt. 



De paa Side 40 omtalte uregelmæssige Atleiringer af 

 brunt Sand og Sandler, der forekommer i Syd og Sydvest 

 for Beeren Eiland. kan maaske ogsaa med Hensyn til sin 

 Dannelse staa i Forbindelse med denne 0. 



Brunt Ler. 

 (Overgangsler os Biloculinler). 



Ved Dybder, 'der er større end 500 Favne, fineler 

 man i Almindelighed Bunden bedækket af et bruntfarvet 

 Sediment. Dette er i Begyndelsen af sin Optræden mindre 

 fint og ensartet (sandholdigt) og af en mere graalig Farve 

 end længere ud i Havet, hvor Biloculinerne forekommer. 

 De Grændser, indenfor hvilke disse Foraminiferer med 

 Regelmæssighed og i større Antal optræder, ligger i Almin- 

 delighed et godt Stykke indenfor det brune Lers egentlige 

 Omraade. Den mere eller mindre brede Strimmel af brunt 



Den norske Nordhavsexpedition Schmelck: Chemi. 



been lying at the bottom of the sea. Nav. fchis view will 

 appear still more plausible if we call to mind the case — 

 isolated, it is true -- in which I succeeded in determining 

 the oxidation of oceanic deposit after exposure to atmo- 

 spheric influence. This change in chemical composition 

 must accordingly be verv slow on the sea-bed. 



Meainvbile. I would by no means venture to imply. 

 that the above explanation is correct; it has weak 

 points, I freely admit. and has therefore been advanced 

 suggestively, with the object of drawing attention to the 

 characteristic results of oxidation in the various deposits. 

 Many other conditions must be tåken into account ere this 

 question can be decided. Tims. for instance, the living or- 

 ganisms that occur in the deposit contribute beyond a doubt 

 in some measure to its oxidation. In particular, red oxide 

 of iron is frequently found deposited on the clay where 

 Annelids have excavated their passages; and numerous spe- 

 cies of Foraminifera operate with a like result, their shells 

 being rich in oxide of iron. As previously stated, Rhab- 

 dammina clay contains very few animal remains. 



One of the mineral fragments brought up in the East 

 Sea. at Station 267. I have submitted to analysis. It was 

 a piece of finely granulated, bluish-grey sandstone. with a 

 large admixture of cementitious lime (calcareous sandstone). 

 In the hydrochloric acid decoction of this mineral substance 

 - prepared precisely as was that for analysing the samples 

 of the bottom — I determined: — 



1.38 per cent of FeO and 0.59 per cent of Fe,,0 3 . 

 accordingly the same proportion as in Rhabdammina clay. 



From what has been stated in the description of the 

 green clay. it is obviously impossible to define with accu- 

 racy the southern and western limits of the Rhabdammina 

 clay,' the necessary observations not having been tåken in 

 that part of the North Atlantic. The last Dutch Expedi- 

 tion. however. took a series of soundings between Vardø 

 antl Beeren Eiland. but those explorers did not pay any 

 particular attention to the nature of the sea-bed. 



The exceptional surface-layers of brown sand and 

 sabulous clay mentioned on page 40. and occurring south 

 antl south-west of Beeren Eiland. may possibly as regards 

 their formation be connected with that island. 



Brown Clay. 

 (Transition Clay and Bilooulina Clav.i 



At depths exceeding 500 fathoms. a brown-coloured 

 clay is generally found to constitute the surface-layer ot 

 the bottom. Where it first occurs. this deposit is 

 coarser and less homogeneous in substance (sabulous). 

 and of a grever sliade than farther from the coast. 

 where its chief characteristic consists in the presence of 

 Biloculinæ. The limits for the occurrence of tbese Fora- 

 minifera as a constant feature and in greater numbers. 

 reach as a rule a good distance within the true province 



